In existing coaxial connectors adapted to be mounted on a panel, the conductive outer contact of the connector also serves as the connector body. Thus, when the contact is mounted in a panel of conductive material, the outer contact, being in electrical contact with the panel, is normally shorted to other contacts on the panel and to ground (or to whatever other potential the panel may be at). There are, however, applications where the shorting together and/or shorting to ground of the coaxial connector outer contacts cannot be tolerated.
For these applications, various techniques have been developed for insulating the connector outer conductor from the panel. The most common technique presently utilized to insulate the connector is to insert an insulating bushing between the connector body and the panel. This method also requires that an additional insulating washer be added between the lock washer or nut utilized for securing the connector in the panel and the panel. Another technique which may be utilized to isolate the panel connector from the panel (ground) is to mount an insulating sleeve over the connector body, the sleeve being the only element which makes contact with the panel, the locking nut, etc., when the connector is mounted in the panel.
While the techniques indicated above provide an insulated-from-ground bulkhead or panel connector, they suffer from a number of substantial shortcomings. First, when an insulated-from-ground connector is utilized in place of a standard panel connector, at least one, and sometimes two, extra parts are required. These additional parts must be handled and assembled on the connector when the connector is mounted. Thus, because of these extra parts, the insulated connector is significantly more expensive to manufacture and utilize than standard panel connectors.
Second, the extra washer, sleeve flanges, or other elements required for insulating the connector from the panel have a finite thickness which means that, for a given size connector, the maximum panel thickness which can be accommodated is reduced. Further, the addition of a bushing or sleeve on the connector increases the diameter required for the mounting hole. If standard size mounting holes have already been punched in the panel, this means that the panel will have to be repunched, or otherwise operated on to increase the hole diameters. The increased diameter required for the holes also reduces the connector density which may be accommodated on a panel. The reduction in panel thickness and in the amount of material between mounting openings combine to reduce the strength of the mounting panel.
In summary, it is seen that standard insulated-from-ground panel connectors are significantly more expensive to manufacture and utilize than standard panel connectors in that (1) they require additional parts; (2) the additional parts must be assembled, increasing the assembly cost; and (3) either standard size mounting openings must be enlarged, possibly requiring the purchase of special tooling to perform this function, or an inventory must be maintained of panels having two different size mounting holes.
From the above it is apparent that a requirement exists for a panel connector, the conductive body of which may be easily insulated from ground without resulting in any increase either in the size of the connector or in the cost of manufacturing and assembling it.